The first study into bumblebee colour patterns to cover all species around the world has been published.
Bee expert at the Natural History Museum, Paul Williams, demonstrated that different groups of bumblebees with particular colouring are concentrated in different parts of the world.
For example, black bumblebees with red tails are especially common in northwest Europe, in countries such as Germany and the Netherlands. Red colouring is rare among North American species. And bumblebees with bright white bands are very common in the higher mountains of southern Asia, in places such as Turkey and the Himalaya.
Williams studied specimens from the Museum’s vast collections and also travelled to China, India, Europe, and North America to investigate the insects. He had to look at more than 1000 different colour patterns in just the females!
Scientists had previously thought that being entirely black-haired would be most useful for a bee in northern temperate regions to allow it to absorb heat from the sun and get warm on cold mornings. However, all-black bumblebees are concentrated in the tropics, in countries such as Ecuador and Peru.
In contrast, the palest bumblebees are concentrated at mid-northern latitudes, for example in Mongolia, northern China and Korea. Their colour may help to camouflage them in summer grasslands as they dry and turn yellow.
The most familiar striped bumblebees are widespread, but are especially common in mountains. Their bold patterns may help to protect them against predators by warning of their sting.
The term ‘bees’ is used for honeybees, bumblebees and other solitary species. They travel from plant to plant transferring pollen as they gather nectar for food.
All bees are extremely important for pollinating crop plants, such as cucumbers, peppers, tomatoes, strawberries, apples, avocado, cashew nut, peanut, grapes, olive, coffee and many more. Pollination by bees accounts for 85% of the value of all insect pollinated crop plants in Europe.
There are 267 species of bee in the UK, including many that are under threat of extinction. Of the 25 bumblebee species in Britain, some have declined in numbers. This seems to be due to habitat loss and the loss of certain flower species, such as red clover that seems to be especially important for some bumblebees.
In the future, scientists will look at the evolution of bumblebee colour patterns in more detail by studying bumblebee DNA.
Find out more at www.nhm.ac.uk/research-curation/projects/bombus/